Automatic cut-off for gas burners



y 17, 1932- I A. H.-DAVlS, JR 1,858,986

AUTOMATIC CUT-OFF FOR GAS BURNERS Filed Aug. 18, 1928 Patented May 17, 1932 ARGHIIBALD H. DAVIS, JR., 013 BUFFALO, NEW

PATENT OFFICE &; CHEMICAL COMPAN Y, INCL, OF N EW YoR-KpN'. Y., A CORPORATION OF NEW YQRK AUTOMATIC CUT-OFF FOR GAS BURNER/S Application filed August 18, 1928. Serial N'o. 300,587,

This invention relates to an automatic cutoff for gas burners, and comprises a means whereby the flow of gas is completely arrested when the pressure in the gas line falls below a predetermined minimum and a means whereby resumption of the flow of gas is thereafter prevented.

In the operation of a gas fired furnace it sometimes happens that the pressure in the gas main fails, thereby causing a cessation in the flow of gas to the gas burned whereupon the flame is extinguished. When the flow of 'as is again resumed the fire box of the furnace becomes filled with an explosive mixture of gas and air. If an operator, unaware that gas has been flowing, attempts to relight the burner under such circumstances, an explosion of the gas mixture in the furnace may occur with consequent damage. In the type of furnace having a draft only when gas is burning, a further hazard arises in the danger of explosion in the room under the.

above circumstances, due to the gas escaping into the room.

One object of the present invention contemplates the elimination of the hazard of explosion in the operation of a gas fired furnace, due to failure of pressure in the gas main. simple and efficient means having no relatively moving parts, whereby the feed to the gas burner is completely obstructed when the pressure in the gas main falls below a predetermined minimum and a means to thereafter prevent resumption of the gas flow until the obstruction is manually removed.

These and other objects will be readily apparent from a consideration of the following specification taken in connection with the drawings wherein is disclosed a preferred embodiment of the invention and wherein Fig. 1 is a view partly in section, v Fig. 2 is a side view of Fig. 1 partly in section,

Fig. 3 is a section of line 33 of Fig. 1. Referring to the drawing, a U-shaped member or trap 1 is interposed between the burner and the gas supply main and consists of the hollow vertical sections 2 and 3 and a horizontal section 1 joining the two vertical shown).

A further object contemplates a sections at their bottoms. Gas enters the member at 5, passes through the sections 2, 3, and- 4 and through pipe 6 to the burner (not A pipe or drain 7 inthelower horizontal section 4: communicates with the interior of the U-member and is normally closed by thevalve 8. Adjacent to the U-shaped member is a manometer device consisting of a tank or receptacle 9 into'which water is introduced through 10 and discharged through a con stantlevel overflow l1. Extending downwardly from the bottom of the receptacle 9 is the Ueshaped section of the manometer consisting of legs 12, 13, a horizontal section 14 joiningthe two legs at the bottom, and a connecting arm 15 having the valve 1?, joining the leg 12 and manometer to the leg 2 of the U-shapedmember at 16.

In operation, gas from the main line passes into the U-shaped member through 5,

through vertical leg 2, through horizontal section 4, through vertical leg 3, and leaves through pipe 6 to the gas burner. 'The manometer device contains water at a predetermined constant level. l/Vhen the pressure in the gas line is above a predetermined minimum, some gas will enter the connecting arm 15 and the vertical leg 12, forcing back the water in leg 12. The height of the water in leg 12 will therefore depend solely upon the pressure in the gas main. As the pressure in the gas main diminishes, the column of water in leg 12 will rise until the minimum gas pressure permissible has been reached whereupon the water will flow through connecting arm 15 into the vertical leg 2 at 17 and will flood the U-bend up to the point 17, thus effectively shutting ofl" the supply of gas to the burner. Before communication with the burner can be reestablished, it will be neces- YORK, ASSIGNOR T0 NATIONAL ANILINE sary to drain the water out of the U-member ter back in leg 12, where it will be held until the gas pressure again drops below the minimum value permissible. The apparatus is now ready for operation. While I have shown and described the preferred embodiment of the invention, therein a U-bend is formed in the gas line, I wish it to be understood that the shape of this member is not material and that the only requirement as to the form ofthis member is that there shall be an oflset or a pocket formed in the gas line which will completely obstruct the gas flow when filled with a liquid. The length of the legs Zand 3 of the U-shaped member will be such that when'it is flooded, the gas pressure in leg 2 will not be strong enough to force the liquid up throughleg 3 and into exit pipe 6 leading to the burner. The particular form of the manometer also is not material, it being necessary only that there be a source of liquid under constant pressure operated by changing pressure in the gas main to introduce said liquid into the main. Other changes in the construction of details of the invention will be readily apparent to those skilled in the'art The invention is not to be limited, except as defined in the following claim,

' I claim 5 i In an apparatus of the character described, the combination comprising a gas conduit having a U-shaped portion, a manometer having one end communicating with one leg of the Uat a point substantially above the base of, the U, a reservoir in communication r with the other endor' the manometer, and an overflow pipe to maintain a constant level of liquid'in said reservoir. I V 8 In testimony whereof I afiixniysignature Q A IB L DA R. 

